﻿Shader "Unlit/Gray"
{
    Properties
    {
        [PerRendererData] _MainTex("Sprite Texture", 2D) = "white" {}
        _Color("Tint", Color) = (1,1,1,1)

        _StencilComp("Stencil Comparison", Float) = 8
        _Stencil("Stencil ID", Float) = 0
        _StencilOp("Stencil Operation", Float) = 0
        _StencilWriteMask("Stencil Write Mask", Float) = 255
        _StencilReadMask("Stencil Read Mask", Float) = 255

        _ColorMask("Color Mask", Float) = 15

        [Toggle(UNITY_UI_ALPHACLIP)] _UseUIAlphaClip("Use Alpha Clip", Float) = 0
        [Toggle] _GrayOnly("GrayOnly",Float) = 0
    }

        SubShader
        {
            Tags
        {
            "Queue" = "Transparent"
            "IgnoreProjector" = "True"
            "RenderType" = "Transparent"
            "PreviewType" = "Plane"
            "CanUseSpriteAtlas" = "True"
        }

        Stencil
        {
            Ref[_Stencil]
            Comp[_StencilComp]
            Pass[_StencilOp]
            ReadMask[_StencilReadMask]
            WriteMask[_StencilWriteMask]
        }

            Cull Off
            Lighting Off
            ZWrite Off
            ZTest[unity_GUIZTestMode]
            Blend SrcAlpha OneMinusSrcAlpha
            ColorMask[_ColorMask]

        Pass
        {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag

            #include "UnityCG.cginc"
            #include "UnityUI.cginc"

            #pragma multi_compile __ UNITY_UI_ALPHACLIP

        struct appdata_t
        {
            float4 vertex   : POSITION;
            float4 color    : COLOR;
            float2 texcoord : TEXCOORD0;
        };

        struct v2f
        {
            float4 vertex   : SV_POSITION;
            fixed4 color : COLOR;
            half2 texcoord  : TEXCOORD0;
            float4 worldPosition : TEXCOORD1;
        };

        fixed4 _Color;
        fixed4 _TextureSampleAdd;
        float4 _ClipRect;

        v2f vert(appdata_t IN)
        {
            v2f OUT;
            OUT.worldPosition = IN.vertex;
            OUT.vertex = UnityObjectToClipPos(OUT.worldPosition);

            OUT.texcoord = IN.texcoord;

            #ifdef UNITY_HALF_TEXEL_OFFSET
            OUT.vertex.xy += (_ScreenParams.zw - 1.0)*float2(-1,1);
            #endif

            OUT.color = IN.color * _Color;
            return OUT;
        }

        sampler2D _MainTex;
        float _GrayOnly;

        fixed4 frag(v2f IN) : SV_Target
        {
            half4 color = (tex2D(_MainTex, IN.texcoord) + _TextureSampleAdd) * IN.color;

            //Add Start
            float grey = dot(color.rgb , float3(0.299, 0.587, 0.114));
            color.rgb = half3(grey, grey, grey);
            if(_GrayOnly==1)
             {
                color.rgb=half3(0.587, 0.587, 0.587);
             }
            //Add End

            color.a *= UnityGet2DClipping(IN.worldPosition.xy, _ClipRect);

            #ifdef UNITY_UI_ALPHACLIP
            clip(color.a - 0.001);
            #endif

            return color;
        }
            ENDCG
        }
    }
}